How Space Affects Human Health

What Scientists Can Learn from Studying “Space Twins”

Do you ever wonder what might happen to your health if you spent a significant time in space? The National Aeronautics and Space Administration (NASA) partnered with research scientists all over the country in 2015 to learn more about how living in space for a long period of time affects the human body.

A Northwestern-led research team is one of the 10 NASA-funded groups and is specifically looking at how the space environment affects the microbiota “ecosystem” in the human gastrointestinal (GI) tract. The research team also includes collaborators from Rush University Medical School and the University of Illinois at Chicago.

The Set Up

How exactly does the study work? It all has to do with a set of twins: Scott Kelly spent a year in space, while his identical twin brother, Mark Kelly, spent the year on Earth.

Biological samples from both brothers were collected before, during and after the year, and scientists used DNA sequences to identify the microbes in the gastrointestinal tracts of the two men. This study is one of the first to examine how living at zero gravity for an entire year can affect a human’s gut microbiota. The hope is that the findings can help scientists and physicians better understand the role microbiota plays in human health and disease. Now, two years after the study started, scientists are getting a first peek at what the study might reveal.

Preliminary Findings

Northwestern’s GI tract study is led by Fred Turek, PhD, professor in the Ken and Ruth Davee Department of Neurology, and in Psychiatry and Behavioral Sciences. Turek focused on microbiome, or “bugs” naturally found in the gut which aid in digestion. At all time points (before, during and after the space endeavor), there were viral, bacterial and fungal differences in the twins’ microbiome, which was to be expected given the difference in diet and environment.

But what scientists found most interesting were the differences in microbial species observed in Scott Kelly on the ground versus Scott Kelly in space. There was a change in ratio of two dominant bacterial groups present in his GI tract. The ratio of one group increased in space and returned to pre-space levels once he returned to Earth.

According to NASA, scientists found the situation as a whole to be the perfect opportunity for a nature versus nurture study. 10 different research teams are all studying different aspects of the human response to space including the areas of cognitive performance, behavioral health and molecular studies that look at the way genes are turned on and off as a result of spaceflight, and how stressors like radiation, confinement and microgravity prompt changes in the body’s proteins.

To help piece together a more complete picture of the heath effects of prolonged space missions, the research team plans on working closely with other “Twins Study” teams in the future. The study has already taken a giant leap toward determining how stressful a mission to Mars could someday be on the human body.